DE602005004592T2 - Lithographic apparatus, lighting system and debris collection system - Google Patents

Description

TERRITORY

The The present invention relates to a lithographic apparatus Lighting system and a pollution collecting system.

BACKGROUND

A lithographic device is a machine that has a desired Apply pattern on a substrate, usually on a target area of a substrate. A lithographic device may e.g. B. in the manufacture of integrated circuits (ICs) are used. In this case, a patterning device, which is alternatively referred to as a mask or reticle, for generating a Circuit pattern can be used on a single layer the IC device is to be formed. This pattern can be on a target area (which is part of a chip, a chip or a contains several chips) are applied, with the target area on a substrate (eg, a silicon wafer). The transfer of the pattern takes place typically by imaging on a layer of radiation-sensitive Material (resist), which is arranged on the substrate. As a general rule contains a single substrate is a network of adjacent target areas, which are patterned one after the other. Known lithographic devices are provided with so-called steppers, where each target area is irradiated by the target area each time with an entire pattern is exposed, and with so-called Scanners in which each target area is irradiated by the pattern by means of an irradiation beam in a given direction (the "scan" direction) in a scanning motion is applied while simultaneously the substrate parallel or antiparallel to this direction is scanned. The transferring of the pattern from the patterning device onto the substrate also be carried out by printing the pattern on the substrate.

at A lithographic device is the size of the features that appear on the Substrate can be imaged through the wavelength limited to the projection radiation. To be able to produce integrated circuits that have a higher density of devices and thus higher Working speeds, it is desirable, even smaller To be able to depict characteristics. While in most current lithographic projection devices UV light is used by mercury lamps or excimer lasers has been proposed, shorter wavelengths in the Range of 5 to 20 nm and in particular with a value of about 13 nm to use.

A Such radiation is called extreme ultraviolet radiation (EUV) or soft x-ray radiation designated, and to the possible Sources for that Counting this radiation count z. B. laser-generated plasma sources, discharge plasma sources, or Synchrotron radiation from electron storage rings. For these types of radiation it is necessary that the beam path in the device is evacuated is to avoid scattering and absorption of the beam. There no known material exists for the production of a refractive optical element for EUV radiation is suitable at the for EUV litographic devices mirror in the irradiation (lighting) and Projection systems are used. Even multi-layered mirrors for EUV radiation have relatively low reflectivities and are highly susceptible to contamination, because of their reflectivity and thus the throughput of the devices can be further reduced can. This can result in the vacuum level to be maintained more specifications can be imposed, and in particular necessitate that the hydrocarbon partial pressures be very kept low.

In a typical discharge plasma source, plasma is formed by an electrical discharge. The plasma can then be compressed so that it becomes highly ionized and reaches a very high temperature, causing the emission of EUV radiation. The material used to generate the EUV radiation is typically xenon gas or lithium vapor, although other gases or vapors such as e.g. As cryptone gas or tin or water vapor can be used. However, these gases may have relatively high EUV radiation absorption and / or be detrimental to optical devices further downstream of the projection beam, and therefore their presence in the rest of the lithographic device should be minimized. A discharge plasma source is z. B. disclosed is the United States Patent No. 5,023,897 and the United States Patent No. 5,504,795 ,

In a laser-generated plasma source, a z. B. from (bundled) xenon existing jet can be output via a nozzle. At a certain distance from the nozzle, the beam is irradiated with a laser pulse of suitable wavelength to form a plasma, which subsequently emits EUV radiation. There may also be other materials such. As water droplets, ice particles, lithium or tin vapor etc. ejected from a nozzle and used for EUV production. In an alternative laser-generated plasma source, a solid (or liquid) material is irradiated to produce a plasma for the EUV radiation. Laser-generated plasma sources are z. B. disclosed in the United States Patent No. 5,459,771 , by doing United States Patent No. 4,872,189 and the United States Patent 5,577,092 ,

One common feature of the above Sources is that their operation has a background print of a or multiple source gases (to which also vapors counting) induced in or near the source region.

The Source gases are also those gases or vapors attributable to their plasma must be generated for EUV production, but also gases or vapors, the while a source operation by z. B. laser irradiation of a solid or liquid Material are generated. The source gases should be on the source area limited since they are a considerable one Absorption of EUV radiation may cause or cause contamination or damage in the rest of the lithographic apparatus. Those in the sources gases Existing particles are hereinafter also referred to as impurity particles designated.

International Patent Application Publication No. WO 99/42904 , which is incorporated herein by reference, describes a multi-foil filter, often referred to as a so-called "foil trap", which in use is oriented such that radiation along the foil propagates through the filter as such that impurity particles moving away from the propagation direction of the radiation are trapped by the films. A buffer gas is supplied to cool the contaminant particles and thereby increase the likelihood of the contaminant particles being caught by the foils.

The European Patent Publication No. 1,329,722 A2 , which is mentioned here for purposes of comparison, describes the use of a buffer zone separated from a source zone in which the radiation is generated. Between the source zone and the buffer zone a wall is positioned. The wall is provided with a jet aperture for transmitting the radiation from the source zone to the buffer zone. Buffer gas is supplied to the buffer zone, and buffer gas is taken out from the buffer zone such that the pressure in the buffer zone is lower than or equal to the pressure in the source zone to prevent a flow of buffer gas into the source zone and thereby the occurrence of a buffer gas Prevent pressure increase in the source zone.

International patent application publication no. WO 03/034153 describes the use of a so-called impurity trap having two sets of channels arranged radially about the optical axis and in series relative to each other. A space between the two sets of buffer gas is supplied. A portion of the gas flows from that space to a radiation input of the first set of channels, and another portion of the gas flows through a radiation outlet of the second set of channels.

US 2004/0108465 describes a so-called contamination trap with two sets of channels arranged radially about the optical axis and in series relative to each other. A buffer gas is not supplied. WO 03/087867 describes an impurity trap with two sets of channels. Buffer gas is supplied upstream of the space located between the two sets of channels and discharged to that space.

OVERVIEW

It is desirable to provide a contaminant collecting system having a high pressure of the Buffer gas relative to the source gas allows for the possibility to increase, that the contaminant particles are detected by the system while at the same time a high radiation passage through the system is made possible.

Further it is desirable to provide a lithographic apparatus and a lighting system, which is provided with such a contaminant collecting system.

According to one aspect of the invention, there is provided a lithographic apparatus according to claim 1, comprising a lighting system configured to condition an irradiation beam. The illumination system includes a source for generating radiation and an impurity capture system for capturing at least some of the contaminant particles released upon generation of radiation. The apparatus further comprises a patterning device for patterning the conditioned radiation beam and a projection system for projecting the patterned radiation beam onto a target region of a substrate. The contaminant collection system includes a first set of channels. Each channel of the first set allows the propagation of radiation from the source through the channel and has an interior wall for detecting contaminant particles. The contaminant collection system further includes a second set of channels disposed with respect to the propagation direction of the radiation downstream of the first set of channels. Each channel of the second set allows the propagation of radiation from the source through this channel and has an inner wall for detecting impurity particles. The contaminant collection system further includes a gas supply and a gas outlet located at a location between the first set of channels and the second set of channels to produce a gas flow having a net flow direction that is substantially transverse to the direction of propagation of the radiation.

According to one Aspect of the invention is a lighting system according to claim 16 created to condition a radiation beam in a litographic Device is configured. The lighting system has a Source for generating radiation and an impurity capture system to capture at least some of the contaminant particles, which are released in the generation of radiation. The impurity catchment system contains a first set of channels. Each channel of the first sentence allows the propagation of Radiation from the source through the channel and has a Inner wall for detecting impurity particles. The impurity catchment system contains and a second set of channels related to the direction of propagation the radiation downstream from the first set of channels is arranged. Each channel of the second set allows the Propagation of radiation from the source through this channel and points an inner wall for detecting impurity particles. The Contami nigungsauffangsystem also has a gas supply and a Gas outlet on, at one between the first set of channels and the second set of channels located to a gas flow with a net flow direction essentially transverse to the propagation direction of the Radiation passes.

According to one Aspect of the invention is formed according to claim 31 Pollution trapping system for capturing at least some of the Pollution particles created in the generation of radiation be released. The contaminant collection system includes a first set of channels. Each channel of the first sentence allows the propagation of Radiation from the source through the channel and has a Inner wall for detecting impurity particles. The impurity catchment system contains and a second set of channels related to the direction of propagation the radiation downstream from the first set of channels is arranged. Each channel of the second set allows for propagation radiation from the source through this channel and has an inner wall for detecting contaminant particles. The impurity catchment system further comprises a gas supply and a gas outlet, which at a between the first set of channels and the second set of channels located to a gas flow with a net flow direction essentially transverse to the propagation direction of the Radiation passes.

at Can operate in the first set of channels entering particles from the inner walls of the first set of channels be recorded. Contamination particles that occur when entering in the first set of channels move along the propagation direction of the radiation and that from the first set of channels Escape, be with the highest Probability deflected by means of the buffer gas, the net flow across to the gas propagation direction runs and that are provided in the space between the two sets of channels. The impurity particles as such become most likely from the Innenwän the of the second set of channels captured or even together with the buffer gas from the space between the two channels away. The first set of channels and bring the second set of channels a big Resistance to a gas flow from between the two sets of channels Clean up. This makes possible, that the pressure of the buffer gas in the space between the two sets of channels is relatively high, so the effectiveness of the buffer gas slowing down and / or diverting those exiting from the first set of channels Contamination particles is further increased. Because each channel both of the first set of channels as well as the second set of channels propagate the radiation allows, remains the radiation transmission high.

BRIEF DESCRIPTION OF THE DRAWINGS

in the Following will be - however just as an example - embodiments of the invention with reference to the accompanying schematic drawing, in which the same parts throughout with the same reference numerals are and in which the following is shown:

1 schematically shows a lithographic apparatus according to an embodiment of the invention;

2 schematically shows an impurity capture system as part of the lithographic device according to 1 ;

3 shows a schematic cross-sectional view of an embodiment of the contaminant collecting system according to 2 ;

4 shows another schematic cross-sectional view of an embodiment of the contaminant collecting system according to 2 ;

5a shows a first schematic side view of an embodiment of the contaminant collecting system according to 2 ; and

5b shows a second schematic side view of the contaminant collecting system, which is perpendicular to the first side view according to 5a is scheduled.

DETAILED DESCRIPTION

1 schematically shows a lithographic apparatus according to an embodiment of the invention. The apparatus comprises: an illumination system (illuminator) IL configured to condition a radiation beam B (eg, UV radiation or EUV radiation); a holding structure (eg, a mask table) MT configured to hold a patterning device (eg, a mask) MA and connected to a first positioning device PM configured to precisely position the patterning device according to certain parameters; a substrate table (eg, a wafer table) WT configured to hold a substrate (eg, a resist-coated wafer) W and connected to a second positioning device PM configured for precise positioning the substrate according to certain parameters; and a projection system (eg, a position refractive lens system) PS configured to project a pattern applied to the radiation beam B by the patterning device MA onto a target (eg, containing one or more chips) Area C of the substrate W.

The Lighting system can be different types of optical components have, for. As refractive, reflective, magnetic, electromagnetic, electrostatic or other types of optical components or any Combinations thereof, for aligning, shaping or controlling Radiation are provided.

The Holding structure MT holds the patterning device MA, d. H. she carries her weight. She holds the patterning device in a way that is dependent from the orientation of the patterning device, the embodiment the lithographic device and other circumstances, such. B. whether the patterning device kept in a vacuum environment or not. In the holding structure can mechanical, vacuum, electrostatic or other clamping techniques be used to hold the patterning device. The holding structure can z. B. a frame or a table, which is set as desired or can be moved. The support structure can ensure that the patterning device at a desired Position z. B. is arranged relative to the projection system. Any use of the terms "reticle" or "mask" may be synonymous with the more general Expression "patterning device" are understood.

Under The term "patterning device" should be used in the present Use to be understood in a broad sense every device for applying a laser beam with a in its cross section extending pattern is suitable in that a pattern in a target region of the substrate is formed. It should be noted is that the pattern applied to the radiation beam may be not exactly the desired one Pattern in the target area of the substrate corresponds, e.g. If the pattern phase shifting features or so-called assist features contains. As a general rule corresponds to the applied to the radiation beam pattern of a certain functional layer in a device that in the Target area is formed, such. B. an integrated circuit.

The Patterning device may be transmissive or reflective. To the Examples of patterning devices include masks, programmable Mirror arrays and programmable LCD panels. Masks are in the lithography Well known and include mask types such. B. binary masks, masks with alternating phase shift and muted phase shift masks as well as different hybrid mask types. In an example of a programmable mirror arrays use a matrix array of small mirrors each of which can be tilted individually, so that the incident Radiation in different directions can be reflected. The tilted mirrors bring a pattern onto a radiation beam which is reflected by the mirror matrix.

Under The term "radiation beam" should be used in the present Use in a broad sense any type of projection system including refractive, reflective, catadioptric, magnetic, electromagnetic and electrostatic optical systems or any combinations be understood as the same for the exposure radiation used or for other factors are suitable, such as. B. for the use of an immersion liquid or the use of a vacuum. Any use of the term "projection lens" can be used here as a synonym for the more general term "projection system".

In The present illustration is the device of the reflective Type (i.e., it uses a reflective mask). alternative For example, the device may be of the transmissive type (i.e. uses a transmissive mask).

The The lithographic apparatus may be of a two (double-level) or more type Substrate tables (and / or two or more mask tables). In such "multi-level" machines, the additional Tables can be used in parallel, or there may be preparatory steps be carried out at one or more tables while a or several other exposure steps.

The The lithographic apparatus may also be of a type in which at least a portion of the substrate from a relatively high liquid Refractive index, e.g. B. water, may be covering the space between to fill the projection system and the substrate. An immersion liquid can also on other rooms the litographic device are applied, for. B. between the mask and the projection system. Immersion techniques are on the area to enlarge the Numerical aperture of projection systems well known. The term "immersion" in this application does not mean that a structure such. As a substrate, in liquid must be immersed, but merely means that during the exposure liquid is arranged between the projection system and the substrate.

According to 1 the illumination device IL receives a radiation beam from a radiation source SO. The lighting system may also be construed as containing the source. However, the source and the lithographic device may be separate units, e.g. When the source is an excimer laser. In such cases, the source is not considered part of the lithographic apparatus, the radiation beam is by means of a Strahlzuführsystems, z. B. has appropriate alignment mirror and / or a Strahlerweiterer, output from the source SO to the illumination device IL. In other cases, the source may be an integral part of the lithographic device, e.g. When the source is a mercury lamp. The source SO and the illumination device IL, together with the beam delivery system, if necessary, may be referred to as the irradiation system. The lithographic apparatus may include an impurity capture system D for capturing at least some of the contaminant particles released upon generation of radiation. The contaminant collecting system may be provided as a separate unit, as part of the source or as part of the lighting system.

The Lighting device IL may include an adjustment device for adjustment the angular intensity distribution of the radiation beam. Generally, at least the outer and / or the inner radial dimension (usually referred to as σ-outer or σ-inner dimension) the intensity distribution be set in a pupil plane of the lighting device. additionally For example, the lighting device IL may have various other components included, such as B. an integrator and a capacitor. The Lighting device can be used to condition the radiation beam used to give the beam the desired uniformity and intensity distribution to give in its cross section.

Of the Radiation beam B impinges on the patterning device (eg. the mask MA) attached to the support structure (eg the mask table MT), and is patterned by the patterning apparatus. After he has passed through the mask MA, goes through the Radiation beam B the projection system PS, which the beam to the target area C of the substrate W focused. With the help of the second positioning device PW and the position sensor IF2 (eg an interferometric device, a linear encoder or a capacitive sensor) may be the substrate table precise be moved, z. B. to different target areas in the way of the radiation beam B to position. Similarly, the first positioning device PM and another positioning sensor IF1 can be used to match the mask MA with respect to the path of the radiation beam B to position correctly, eg. B. after the mechanical call from a mask library or while a scanning process. In general, the movement of the mask table MT by means of a module with long stroke (coarse positioning) and a module with short Hub (fine positioning), the part of the first positioning device PM are to be realized. In similar Way, the movement of the substrate table WT by means of a module with a long Hub and a module with short stroke, the part of the second positioning device PW are to be realized. In the case of a stepper (as opposed to a scanner) can be the mask table MT, the mask table either only with a Actuate supply device be connected or fixed with a short stroke. The mask MA and the substrate W can using mask alignment marks M1, M2 and substrate alignment marks P1, P2 aligned become. Although the substrate alignment marks to that effect are shown that their specially assigned target areas can prove she also in rooms be arranged between target areas (these are as write track alignment marks known). In similar Way you can in situations where more than one chip is provided on the mask MA with the mask alignment marks interposed between the chips be.

• 1. In der Schritt-Betriebsart werden der Masken-Tisch MT und der Substrat-Tisch WT im Wesentlichen stationär gehalten, während das gesamte auf den Strahlungs-Strahl aufgebrachte Muster auf einmal auf den Target-Bereich C projiziert wird (d. h. einzelne statische Belichtung). Dann wird der Substrat-Tisch WT in der X- und/oder der Y-Richtung derart verschoben, dass ein anderer Target-Bereich C belichtet werden kann. In der Schritt-Betriebsart begrenzt die maximale Größe des Belichtungsfelds die Größe des in einer einzelnen statischen Belichtung abgebildeten Target-Bereichs C.
• 2. In der Abtast-Betriebsart werden der Masken-Tisch MT und der Substrat-Tisch WT synchron abgetastet, während ein auf den Strahlungs-Strahl aufgebrachtes Muster auf den Target-Bereich C projiziert wird (d. h. einzelne dynamische Belichtung). Geschwindigkeit und Richtung des Substrat-Tischs WT relativ zu dem Masken-Tisch MT können durch die (Ent-)Vergrößerungs- und Bildumkehr-Eigenschaften des Projektionssystems PS bestimmt werden. In der Abtast-Betriebsart begrenzt in einer einzelnen dynamischen Belichtung die maximale Größe des Belichtungsfelds die Breite (in der Nicht-Abtastrichtung) des Target-Bereichs, während die Länge der Abtastbewegung die Höhe (in der Abtastrichtung) des Target-Bereichs bestimmt.
• 3. In einer weiteren Betriebsart wird der Masken-Tisch MT im Wesentlichen stationär gehalten, während er eine programmierbare Musterungsvorrichtung trägt, und der Substrat-Tisch WT wird bewegt oder abgetastet, während ein auf den Strahlungs-Strahl aufgebrachtes Muster auf den Target-Bereich C projiziert wird. Bei dieser Betriebsart wird generell eine gepulste Strahlungsquelle verwendet, und die programmierbare Musterungsvorrichtung wird nach jeder Bewegung des Substrat-Tischs WT oder zwischen aufeinanderfolgenden Bestrahlungsimpulsen während einer Abtastbewegung in der erforderlichen Weise aktualisiert. Diese Betriebsart kann problemlos bei der maskenlosen Litografie angewandt werden, bei welcher eine programmierbare Musterungsvorrichtung verwendet wird, wie z. B. ein programmierbares Spiegel-Array des oben erwähnten Typs.

The device described can be in min at least one of the following operating modes:

• 1. In the step mode, the mask table MT and the substrate table WT are kept substantially stationary while the entire pattern applied to the radiation beam is projected onto the target area C at once (ie, single static exposure). , Then, the substrate table WT is shifted in the X and / or the Y direction so that another target area C can be exposed. In the step mode, the maximum size of the exposure field limits the size of the target area C imaged in a single static exposure.
• 2. In the scan mode, the mask table MT and the substrate table WT are scanned synchronously while a pattern applied to the radiation beam is projected onto the target area C (ie, single dynamic exposure). The speed and direction of the substrate table WT relative to the mask table MT can be determined by the (de) magnification and image inversion characteristics of the projection system PS. In the scanning mode, in a single dynamic exposure, the maximum size of the exposure field limits the width (in the non-scanning direction) of the target area, while the length of the scanning movement determines the height (in the scanning direction) of the target area.
• 3. In another mode, the mask table MT is held substantially stationary while carrying a programmable patterning device, and the substrate table WT is moved or scanned while a pattern applied to the radiation beam is directed to the target area C is projected. In this mode of operation, a pulsed radiation source is generally used, and the programmable patterning device is updated as required after each movement of the substrate table WT or between successive irradiation pulses during a scanning movement. This mode of operation can be readily applied to maskless lithography, which uses a programmable patterning device, such as a laser pointer. For example, a programmable mirror array of the type mentioned above.

It can also combinations and / or variations of the types of use described above or completely different uses.

2 schematically shows an impurity capture system D as part of a lithographic device according to an embodiment of the invention. The contaminant collecting system D can be considered as a separate unit. However, the contaminant collection system D may also be considered part of the SO source. It is possible to consider the contaminant collecting system D as part of the lighting device IL. This in 2 The system shown may also be considered as an illumination system including a source SO for generating radiation and an impurity capture system D for capturing at least a portion of the contaminant particles released upon generation of radiation. The contaminant collecting system D includes a first set FS of channels C. Each channel C of the first set FS has an inner wall IW for detecting contaminant particles (not shown).

Further each channel C of the first set FS has a channel direction, which makes it possible that radiation R from the source SO propagates through this channel C. The contaminant collection system D further includes a second set SS of channels C. The second sentence SS of channels C is in relation to the (by arrows at the end of the interrupted Lines R indicated) propagation direction of the radiation downstream of the first sentence FS of channels C arranged. Further, each channel C of the second set has one Inner wall IW for catching impurity particles. Further each channel C of the second set SS has a channel direction, which makes it possible that radiation R from the source SO also through this channel C spreads. The contaminant collecting system D further includes a gas supply GS and a gas outlet GR to switch between the first Set FS of channels C and the second set SS of channels C a gas stream F with a net flow to apply, which is essentially transverse to the direction of propagation the radiation R passes.

contaminant particles (not shown) extending in the direction of propagation through the channels C of the first set FS have been moved by clash with the gas particles of the gas supplied from the gas supply GS distracted. This enlarges the Probability that the contaminant particles from an inner wall one of the channels C of the second sentence SS are recorded.

The contaminant collecting system D is arranged to generate and maintain, at least during the operation of the source SO between the first set FS of channels C and the second set SS of channels C, a gas pressure which is much higher than the gas pressure applied to one Radiation input RE of the first set FS of channels C is present, and / or the gas pressure which is present at a radiation output RX of the second set SS of channels C. A high gas pressure allows for a relatively small interaction length of the gas and the contaminant particles that form from the first set FS of channels C to the second set SS of channels C. The high gas pressure can easily z. B. controlled by controlling the gas supply and the gas discharge. The resistance of the channels C reduces the likelihood that the buffer gases will move through the channels C to the source SO or to the lighting device IL. In what follows, what considerations can be applied when determining the required resistance or conductivity of the channels for gas moving through the channels. In general, the longer the channels are, the higher the resistance the gas will experience as it moves through that channel. In this sense, the low interaction length that is possible due to the high gas pressure in the space between the two sets of channels also allows for the design of relatively long channels and thus higher resistance of these channels to gas moving through the channels in a situation where in which the available distance between the source and the lighting device is limited. It should be noted that this feature is also beneficial to the source since the correct operation of the source provides a limitation on the maximum allowable pressure at the source. In a sense, the source is isolated from the "gas chamber" existing between the first set of channels and the second set of channels. The gas chamber remains optically connected to the source. Strong impurity suppression, defined as the product of the pressure and the distance over which the pressure stops, can still be achieved. Finally, the pressure can be relatively high, which compensates for the relatively small distance between the two sets of channels. Due to the possible high buffer gas pressure and the relatively large channels of the first set of channels and the second set of channels, which in practice results in a relatively small distance between the two sets of channels, a relatively high suppression of impurities per unit length can be achieved ,

The Contaminant collection system D may be arranged such that it's a gas flow F with a net flow direction generated, which is essentially normal at least part of a the interior walls IW of the second sentence SS of channels C runs. This increases the probability that the inner walls IV of the second set SS of channels C are able to trap the contaminant particles which have been deflected by the interaction with the buffer gas. each Inner wall IW of the second set SS of channels C can essentially just be. This causes a further increase in the probability that the contaminant particles deflected by interaction with the buffer gas from the inner walls IW of the second set SS of channels C be caught. It is possible, an inner wall IW of the second set SS of channels C in the Substantially parallel to another inner wall IW of the second Set ss of channels C runs. This can be another increase the probability that the deflected by the buffer gas Contaminant particles from the inner walls IW of the second set SS of channels C be caught.

In particular, show 5a and 5b schematically an impurity capture system as part of a lithographic device according to an embodiment of the invention, in which at least a part and, as shown, even the entirety of the inner walls of the second set of channels are formed by films or plates. This embodiment will be explained in more detail below.

It is also possible that each channel of the second set of channels has a cross-section with a closed geometric shape extending substantially in the direction of propagation of the radiation. 3 and 4 Fig. 12 schematically shows a cross-section of a contaminant collecting system provided as part of a lithographic apparatus according to such an embodiment or embodiments of the invention. The in 3 The cross section shown may be a cross section along the line I, may have a cross section along the line II, or a cross section along both the line I and the line II in 2 represent. In the 4 The cross-sections shown may also be a cross section along the line I, may have a cross section along the line II, or a cross section along both the line I and the line II in FIG 2 represent. A set of channels with a cross section according to 3 or 4 causes greater resistance to gas moving through these channels than a set of channels formed by parallel plates each lying in a straight virtual line.

Of course, the smaller the cross section of each channel, the greater the resistance to which a gas strikes as it passes through the channel. Those skilled in the art will be able to estimate the number of channels based on the required radiopacity of such a set of channels and on the required resistance that such a set of channels should oppose to gas passing through those channels optimize. As mentioned above, the length of these channels is also taken into account. Even though 3 circular cross sections of the channels and 4 shows rectangular cross sections of the channels, it should be noted that the invention is not limited to these cross sections. For example, honey too honeycomb cross-sections or other optimized cross-sections be appropriate. Furthermore, not all channels of a set of channels necessarily need to have the same cross-section.

It it is possible, that the inner wall IW of one or each channel C of the second set SS of channels C substantially coincides with a virtual cone whose tip coincides with the source SO. In such an embodiment are the shapes of the channels configured such that the radiation emerging from the source SO can extend in the radial direction.

So far, the second set of channels has been explained. The following description will focus on the first set FS of channels C. In one embodiment, the contaminant collection system is arranged to effect such a gas flow that the net flow direction is substantially parallel to at least a portion of one of the inner walls of the first set of channels , 5a schematically shows an impurity capture system D as part of a lithographic apparatus according to an embodiment of the invention, in which the gas flow is provided such that the net flow direction is substantially parallel to at least a part of one of the inner walls of the first set of channels. In fact, as shown, each inner wall of the first set of channels is substantially planar. This (virtual) plane intersects the source SO. The above-mentioned advantages for the configuration of the second set of channels are also given here.

In the context of this description, the inner walls of the first set of channels are substantially parallel in configuration with respect to each other, although not in the strict sense of the word "parallel". This also applies to the in 5b shown second set of channels. At least a part of an inner wall of the first set of channels is formed by a foil or plate. By providing the gas flow F such that the net flow direction is substantially parallel to at least part of the inner walls of the first set of channels, at least a portion of the gas flow F is maintained in a direction along the inner walls of the first set of channels across Propagation direction of the radiation is.

In the embodiment according to 5a - in which 5a shows a first side view of the contaminant collecting system D - the gas flows in the direction normal to the plane of the drawing. 5b schematically shows a further side view, which is perpendicular to the side view according to 5a runs. In 5b the gas flow is indicated by the arrow F. As mentioned above, the second set of channels in the gas stream are oriented relative to one another such that the net flow direction of the gas stream is substantially parallel to the inner walls of the second set of channels.

Also for the embodiment according to 5a and 5b It is true that the source SO is not exposed to high gas loads. Although the first set FS of channels C is relatively permeable to the gas flow F, the resistance experienced by the flow F as it moves towards the source SO is such that no large amount of gas reaches the source SO. Further, the resistance experienced by the gas flow as it moves toward the gas outlet GR is much less than the resistance to which the flow is exposed when moving toward the source, and consequently, the gas tends to close the gas outlet GR to move to the source SO. The space SP between the two sets of sheets can be minimized because the pressure can be kept relatively high, and thereby relatively little "impurity suppression length" is lost as compared to a sheet catcher having a single set of channels and an overall length similar to the length from the radiation inlet RE to the radiation outlet RX of the contaminant collecting system D according to FIG 2 and 5a and b.

It should be understood that also in this embodiment, the inner wall IW of each channel C of the first set FS of channels C may have a cross-section with a closed geometric shape substantially in the propagation direction of the radiation. Further, the inner wall IW of each channel C of the first set FS of channels C may substantially coincide with a cone whose apex coincides with the source SO. In this case, the flow direction of the buffer gas is not further passed through the inner walls of the first set FS of channels C. However, the resistance of the channels C to a gas moving through the channels C to the source SO is substantially higher than that in FIG 5a shown first set of channels.

It should be understood that those skilled in the art should be able to do without difficulty, for example, according to the first set of channels 2 in which the channels z. B. inner walls having a trained as a closed geometric shape cross-section, with a second set of channels according to 5b to combine. Also a combination of the first set of channels according to 5a and a second set of channels according to 2 whose inner walls formed as a closed geometric shape cross section forms an embodiment which is part of the invention explained in this description. It should also be appreciated that the contaminant collection system can be rotated about an axis coincident with a virtual line passing through the source. In such an embodiment, the flow direction of the buffer gas is preferably rotated at a rotational speed equal to the rotational speed of the first and second sets of channels.

Even though in this description specifically to the use of a lithographic Device in the production of ICs, it is pointed out that with the lithographic apparatus described herein also other applications can be handled, z. For example, the manufacture of integrated optical systems, and detection patterns for Magnetic domain memory, flat-panel displays, Liquid crystal display devices (LCDs), thin-film magnetic heads etc. The savvy technician will be familiar with that in context such alternative use cases any use of the terms "wafer" or "chip" as synonymous with the more general terms "substrate" or "target area" can. The substrate referred to herein may be before or after exposure, for example, in a conductor track apparatus (a tool that typically has a resist layer on it Apply substrate and the exposed resist develops), a metrological tool and / or an inspection tool. The present disclosure can in cases in which an appropriate applicability is given in context used with these and other substrate processing tools become. Furthermore, the substrate can be processed more than once, z. B. to produce a multilayer IC device, so that the term "substrate" as used herein may also refer to a substrate, which already contains several processed layers.

Even though specifically to a use of embodiments of the invention in the context of optical lithography, will be apparent Be that invention for others use cases is suitable, such. For example the printing lithography, and that the invention where the context is allowed, not limited to optical lithography. In lithographic printing, a topography defines in a patterning device the pattern generated on the substrate. The topography of the patterning device can be pressed into a resist layer applied to the substrate, whereupon the resist is applied by applying electromagnetic radiation, Warmth, Pressure or a combination of these agents is cured. The patterning device is moved out of the resist, with a pattern in the resist after it has hardened.

The Expressions "radiation" and "ray" include in the present use all types electromagnetic radiation including ultraviolet (UV) radiation (eg with a wavelength of about 365, 355, 248, 193, 157 or 126 nm), extreme ultraviolet (EUV) radiation (eg with a wavelength in the range of 5-20 nm) and (soft) X-radiation.

Of the Expression "lens" can be where the Context allows, to every type of optical component including refractive, reflective, magnetic, electromagnetic and electrostatic optical components, or any combination of such types Respectively.

Even though above certain embodiments of the invention, it will be apparent that the invention also practiced in a form other than that described herein can be. For example, the invention may be in the form of a computer program, containing one or more sequences of machine-readable instructions including Method according to the above Disclosure, or as a data storage medium (eg, as a semiconductor memory, as a magnetic or optical disk) in which such a computer program is stored.

The The above descriptions are illustrative and are not in the sense of a restriction to understand. Thus, it will be apparent to those skilled in the art, that modifications are made to the invention described herein can, without departing from the scope of the following claims.

Claims (45)

A lithographic apparatus comprising: an illumination system configured to condition an irradiation beam, the illumination system including an impurity capture system (D) for capturing at least some impurity particles released upon generation of radiation (R) by a radiation source (50), and a projection system for projecting the radiation beam at a target area of a substrate, the contaminant collection system comprising: (i) a first set of channels (FS), each channel of the first set transmitting radiation from the source and having an interior wall for detecting contaminant particles ; (ii) a second set of channels (SS) pointing in relation to the propagation direction of the radiation downstream of the first set of channels each channel of the second set also transmits radiation from the source and has an interior wall for detecting contaminant particles; and characterized in that the contaminant collection system further comprises: (iii) a gas supply (GS) and a gas outlet (GR) located at a location between the first set of channels and the second set of channels to provide a gas flow (F ) whose net flow direction is substantially transverse to the propagation direction of the radiation. A lithographic apparatus according to claim 1, wherein the contaminant collecting system is designed such that it at least during the operation of the source between the first set of channels and the second set of channels generates and maintains a gas pressure higher than that at a radiation inlet of the first set of channels existing gas pressure and / or at a radiation outlet of the second set of channels existing gas pressure. A lithographic apparatus according to claim 1, wherein the contaminant collecting system configured to generate a Gas flow such that the net flow direction substantially normal to at least a part of one of the inner walls of the second set of channels runs. A lithographic apparatus according to claim 3, wherein at least a portion of one of the inner walls of the second set of channels is formed by a foil or plate. A lithographic apparatus according to claim 3, wherein one of the interior walls of the second set of channels essentially parallel to at least one further inner wall of the second set of channels runs. A lithographic apparatus according to claim 5, wherein each inner wall of the second set of channels is substantially planar. A lithographic apparatus according to claim 3, wherein each channel of the second set of channels is substantially rectangular for propagation direction of radiation a cross section with closed geometric Has shape. A lithographic apparatus according to claim 3, wherein each channel of the second set of channels is essentially one coincides virtual cone and wherein, in use, the top of the cone coincides with the source. A lithographic apparatus according to claim 1, wherein the contaminant collecting system configured to generate the gas stream such that the net flow direction substantially parallel to at least a part of one of the inner walls of the first set of channels runs. The lithographic apparatus according to claim 9, wherein at least a portion of one of the inner walls of the first set of channels a foil or plate is formed. The lithographic apparatus according to claim 9, wherein one of the interior walls of the first set of channels essentially parallel to at least one further inner wall of the first set of channels runs. The lithographic apparatus according to claim 11, wherein each inner wall of the first set of channels is substantially planar. The lithographic apparatus according to claim 9, wherein each channel of the first set of channels is substantially rectangular to the propagation direction of the radiation a cross section with closed geometric Has shape. The lithographic apparatus according to claim 9, wherein each channel of the first set of channels is essentially one Cone agree and wherein, in use, the top of the cone coincides with the source. A lithographic apparatus according to claim 1, wherein the contaminant collecting system is rotatable about an axis which coincides with a virtual line passing through the source. An illumination system configured to condition an irradiation beam in a lithographic apparatus, the illumination system comprising: a source (50) for generating radiation (R); an impurity capture system (D) for capturing at least some contaminant particles released upon generation of radiation; wherein the contaminant collection system comprises: (i) a first set of channels (FS), each channel of the first set transmitting radiation from the source and having an interior wall for detecting contaminant particles; (ii) a second set of channels (SS) disposed with respect to the propagation direction of the radiation downstream of the first set of channels, each channel of the second set also transmitting radiation from the source and having an interior wall for detecting contaminant particles ; and characterized in that the contaminant collection system further comprises: (iii) a gas supply (GS) and a gas outlet (GR) located at one between the first set of channels and the second set of channels located to produce a gas flow (F) whose net flow direction is substantially transverse to the propagation direction of the radiation. Lighting system according to claim 16, wherein the Contaminant collection system is designed such that it at least while the operation of the source between the first set of channels and the second set of channels generates and maintains a gas pressure higher than that at a radiation inlet of the first set of channels existing gas pressure and / or at a radiation outlet of the second set of channels during operation existing gas pressure. Lighting system according to claim 16, wherein the Contaminant collection system configured to generate a gas stream such that the net flow direction substantially normal to at least a part of one of the inner walls of the second set of channels runs. Lighting system according to claim 18, wherein at least a part of one of the interior walls of the second set of channels is formed by a foil or plate. Lighting system according to claim 18, wherein a the interior walls of the second set of channels essentially parallel to at least one further inner wall of the second set of channels runs. A lighting system according to claim 20, wherein each Inner wall of the second set of channels is substantially flat. A lighting system according to claim 19, wherein each Channel of the second set of channels substantially perpendicular to the direction of propagation of the radiation has a cross-section with a closed geometric shape. A lighting system according to claim 18, wherein each Channel of the second set of channels essentially coincides with a virtual cone whose upper End coincides with the source. Lighting system according to claim 16, wherein the Contaminant collection system designed to generate the gas stream such that the net flow direction substantially parallel to at least a part of one of the inner walls of the first set of channels runs. Lighting system according to claim 24, wherein at least a part of one of the interior walls of the first set of channels is formed by a foil or plate. Lighting system according to claim 24, wherein a the interior walls of the first set of channels essentially parallel to at least one further inner wall of the first set of channels. A lighting system according to claim 26, wherein each Inner wall of the first set of channels is substantially flat. The illumination system of claim 24, wherein each Channel of the first set of channels substantially perpendicular to the propagation direction of the radiation has a cross-section with a closed geometric shape. The illumination system of claim 24, wherein each Channel of the first set of channels essentially coincides with a cone, whose upper end coincides with the source. Lighting system according to claim 16, wherein the Impurity collecting system is rotatable about an axis with a virtual line passing through the source. Contaminant collection system to catch at least some impurity particles, which by means of a radiation source in a lithographic system, generating radiation released, wherein the contaminant collecting system (D) comprises: (I) a first set of channels (FS), where each channel of the first set passes radiation from the source and an inner wall for detecting impurity particles; (Ii) a second set of channels (SS), which is related to the propagation direction of the radiation downstream of the first set of channels is arranged, each channel of the second set also radiation let through from the source and an inner wall for detecting impurity particles; and characterized in that the contaminant collecting system further comprising: (iii) a gas supply (GS) and a gas outlet (GR), which is at one between the first set of channels and the second set of channels located location to produce a gas stream (F) whose Net flow direction essentially transversely to the propagation direction of the radiation source coming radiation passes. Contaminant collection system according to claim 31, wherein the contaminant collecting system is adapted to generate and maintain a gas pressure at least during the operation of a radiation source between the first set of channels and the second set of channels which is higher than the gas pressure present at a radiation inlet of the first set of channels and / or the gas pressure present at a radiation outlet of the second set of channels. Contaminant collection system according to claim 31, wherein the contaminant collecting system is configured to generate a Gas flow such that the net flow direction substantially normal to at least a part of one of the inner walls of the second set of channels runs. Contaminant collection system according to claim 33, wherein the at least part of one of the inner walls of the second set of channels is formed by a foil or plate. Contaminant collection system according to claim 33, wherein the one of the interior walls of the second set of channels essentially parallel to at least one further inner wall of the second set of channels runs. Contaminant collection system according to claim 35, wherein each inner wall of the second set of channels is substantially planar. Contaminant collection system according to claim 33, wherein each channel of the second set of channels is substantially rectangular to the propagation direction of the generated by a radiation source Radiation a cross section with closed geometric shape Has. Contaminant collection system according to claim 33, wherein each channel of the second set of channels is essentially one coincides virtual cone and wherein, in use, the top of the cone coincides with a source of radiation. Contaminant collection system according to claim 31, wherein the contaminant collecting system is configured to generate the Gas flow such that the net flow direction substantially parallel to at least a part of one of the inner walls of the first set of channels runs. Contaminant collection system according to claim 39, wherein the at least part of one of the inner walls of the first set of channels a foil or plate is formed. Contaminant collection system according to claim 39, wherein the one of the interior walls of the first set of channels essentially parallel to at least one further inner wall of the first set of channels runs. Contaminant collection system according to claim 41, wherein each inner wall of the first set of channels is substantially planar. Contaminant collection system according to claim 39, wherein each channel of the first set of channels is substantially rectangular to the propagation direction of the generated by a radiation source Radiation a cross section with closed geometric shape Has. Contaminant collection system according to claim 39, wherein each channel of the first set of channels is essentially one coincides virtual cone and wherein, in use, the top of the cone coincides with a source of radiation. Contaminant collection system according to claim 31, wherein the impurity catching system is rotatable about an axis.